Ashlee Simpson s-BABY-large.jpgWe're hearing rumors that Pete and Ashlee's little boy Bronx Mowgli has broken his arm!!!

Ashlee was due in Vegas tonight for the opening night of the ElevenSpa Vegas featuring a hair salon by her pal Ken Paves. Apparently Ash canceled at the last minute, while fellow Paves pal Eva Longoria is at the party right now.

Sources tell X17online Ashlee was forced to back out due to her son's supposed injury but we cannot yet confirm the rumor.

Little Bronx is only 2 1/2 months old :( We hope this isn't true!